目的 研究256层CT对高心率患者 单个心动周期冠状动脉成像的影像学。 方法 选取2014年1月至2017年12月我院心 内科心率≥80次/min疑似冠心病患者134 例作为研究对象，根据扫描实时心率分为 A、B、C组，A组患者心率80-89次/min82 例，B组患者心率90-99次/min29例，C组 ≥100次/min23例。比较患者冠状动脉节 段图图像质量评价等级、冠状动脉节段 标准(STD)和冠状动脉追踪冻结(SSF)质 量评分以及容积CT剂量指数(CTDlvol)、 剂量长度乘积(DLP)以及全身有效剂量 (ED)。结果 134例患者中，A、B、C 3组 冠状动脉阶段图像质量评价为优秀、良 好、中等及差的比较差异无统计学意义 (P＞0.05)，C组患者评价为良好的比例 高于B组、A组，差异无统计学意义(P＞ 0.05)，A组评价为差的冠状动脉节段数较 多，B组与C组评价为差的节段数较少，差 异无统计学意义(P＞0.05)。A、B、C三组 应用SSF重建图像质量等级明显提高，且 可诊断血管节段数明显高于STD质量，差 异具有统计学意义(P＜0.05)，SSF技术 对患者血管支与节段数的可诊断率都明 显高于STD技术，差异具有统计学意义(P ＜0.05)，3组患者CTDlvol、DLP以及ED三 项指标差异无统计学意义(P＞0.05)。结 论 256层CT对高心率患者单个心动周期冠 状动脉成像可行性较高，且具有辐射剂量 较低的特点，采用SSF技术能明显提高影 像质量。

Objective To investigate the application of 256-row detector CT for coronary CT angiography in single cardiac cycle in patients with high heart rate. Methods In this study, 134 cases of suspected coronary artery diseasewith a heart rate of ≥80 beats/min treated in the cardiovascular department of our hospital from January 2014 to December 2017 were selected and divided into three groups according to the real-time heart rate showed by the scan, namely group A (80-89 beats/min, n=82), group B (90-99 beats / min, n=29) and group C (≥100 beats /min, n=23). Then the image quality grade and score of standard (STD) reconstruction and snap shoot freeze (SSF), CT volume dose index (CTDIvol), dose length product (DLP) and effective dose (ED) were compared between groups. Results The proportions of excellent, good, middle and poor imaging quality had no difference among three groups (P>0.05). The proportion of good was highest in group C, and the proportion of poor was highest in group A, with no statistic difference (P>0.05). The diagnosable segmental arteries of SSF were more than that of the STD (P<0.05). The diagnosable branches and segments of SSF were also more than those of the STD (P<0.05). No difference was found in the CTDlvol, DLP and ED between the 3 groups (P>0.05). Conclusion The feasibility of 256-row detector CTor coronary CT angiography in single cardiac cycle in patients with high heart rate is relatively high, which is characterized by the low radiation dosage, and the image quality can be improved with the assistance of SSF.